1. Field of the Invention
The invention relates to a method of image processing for automatically detecting objects of a given type among diffuse objects in an image called original image in the form of a two-dimensional pixel matrix which has digitized intensity values.
The invention likewise relates to a device for implementing this method.
The invention particularly finds its application in the field of radiology for automatically recognizing suspect opacities of a given type in the mammographies, which type corresponds to specific potential cancers.
2. Description of the Related Arts
From the state of the art is already known an image processing method entitled "Multiresolution Analysis of Ridges and Valleys in Grey-Scale Images", published by S. M. GAUCH and S. M. PIZER, published in IEEE TRANSACTIONS ON PATTERNS ANALYSIS AND MACHINE INTELLIGENCE, Vol. 15, No. 6, June 1993. This publication particularly describes a method of detecting ridges and valleys in a three-dimensional image, by searching for the dividing lines of rainfall and the lowest points of the watershed regions of the drainage on the slopes from the ridges. This geographical concept is applied to the two-dimensional images in which intensity levels of the pixels are introduced, or grey levels as a third dimension. According to the described method, the watershed regions and their boundaries are calculated for each image. Thereafter, a hierarchy is imposed on these regions by following the intensity extremes which define each watershed region through multiple resolutions. Then, this hierarchy is used for associating an elimination scale with each boundary curve segment of the watershed region. Finally, a resolution hierarchy is defined with respect to the boundaries of the watershed regions.